Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers (pdf)

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Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers

Braz J Otorhinolaryngol. 2017;83(5):512---522 Brazilian Journal of OTORHINOLARYNGOLOGY www.bjorl.org ORIGINAL ARTICLE Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers夽 Hemanth Narayan Shetty ∗ , Manjula Puttabasappa All India Institute of Speech and Hearing, Department of Audiology, Mysuru, Karnataka, India Received 5 February 2016; accepted 20 June 2016 Available online 14 July 2016 KEYWORDS Frequency following response; Acceptable noise level; Hearing aid performer Abstract Introduction: Hearing aids are prescribed to alleviate loss of audibility. It has been reported that about 31% of hearing aid users reject their own hearing aid because of annoyance towards background noise. The reason for dissatisfaction can be located anywhere from the hearing aid microphone till the integrity of neurons along the auditory pathway. Objectives: To measure spectra from the output of hearing aid at the ear canal level and frequency following response recorded at the auditory brainstem from individuals with hearing impairment. Methods: A total of sixty participants having moderate sensorineural hearing impairment with age range from 15 to 65 years were involved. Each participant was classiﬁed as either Good or Poor Hearing aid Performers based on acceptable noise level measure. Stimuli /da/ and /si/ were presented through loudspeaker at 65 dB SPL. At the ear canal, the spectra were measured in the unaided and aided conditions. At auditory brainstem, frequency following response were recorded to the same stimuli from the participants. Results: Spectrum measured in each condition at ear canal was same in good hearing aid performers and poor hearing aid performers. At brainstem level, better F0 encoding; F0 and F1 energies were signiﬁcantly higher in good hearing aid performers than in poor hearing aid performers. Though the hearing aid spectra were almost same between good hearing aid performers and poor hearing aid performers, subtle physiological variations exist at the auditory brainstem. Conclusion: The result of the present study suggests that neural encoding of speech sound at the brainstem level might be mediated distinctly in good hearing aid performers from that of poor hearing aid performers. Thus, it can be inferred that subtle physiological changes are evident at the auditory brainstem in a person who is willing to accept noise from those who are not willing to accept noise. © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/). 夽 Please cite this article as: Shetty HN, Puttabasappa M. Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers. Braz J Otorhinolaryngol. 2017;83:512---22. ∗ Corresponding author. E-mail: (H.N. Shetty). Peer Review under the responsibility of Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. http://dx.doi.org/10.1016/j.bjorl.2016.06.004 1808-8694/© 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Encoding of speech sounds at auditory brainstem level PALAVRAS-CHAVE Frequência seguida de resposta; Nível de ruído aceitável; Usuário de aparelho auditivo 513 Codiﬁcação dos sons da fala no nível do tronco encefálico auditivo em bons e maus usuários de aparelhos auditivos Resumo Introdução: Os aparelhos auditivos são prescritos para aliviar a perda de audibilidade. Tem sido relatado que cerca de 31% dos usuários rejeitam seu próprio aparelho auditivo devido ao desconforto com o ruído de fundo. A razão para a insatisfação pode estar situada em qualquer local desde o microfone do aparelho auditivo até a integridade de neurônios ao longo da via auditiva. Objetivos: Medir espectros desde a saída do aparelho auditivo no nível do canal auditivo externo e frequência de resposta (FFR) registrada no tronco encefálico de indivíduos com deﬁciência auditiva. Método: Um total de sessenta participantes com deﬁciência auditiva neurossensorial moderada, com faixa etária de 15 a 65 anos foram envolvidos. Cada participante foi classiﬁcado como usuário bom ou mau de prótese auditiva (GHP ou PHP) com base na medida de nível de ruído aceitável (ANL). Estímulos /da / e /si/ foram apresentados em alto-falante a 65 dB SPL. No meato acústico externo, os espectros foram medidos nas condições sem aparelho e com aparelho. No tronco encefálico auditivo, FFR foram registradas para os mesmos estímulos dos participantes. Resultados: Os espectros medidos em cada condição no canal auditivo foram os mesmos em GHP e PHP. No nível do tronco cerebral, melhor codiﬁcação F0; energias de F0 e F1 foram signiﬁcativamente maiores em GHP do que em PHP. Embora os espectros do aparelho auditivo fossem quase os mesmos entre GHP e PHP, existem variações ﬁsiológicas sutis no tronco encefálico auditivo. Conclusão: O resultado do presente estudo sugere que a codiﬁcação neural do som da fala no nível do tronco encefálico pode ser mediada distintamente em GHP em comparação com PHP. Assim, pode-se inferir que mudanças ﬁsiológicas sutis são evidentes no tronco encefálico em uma pessoa que está disposta a aceitar o ruído em comparação com aqueles que não estão dispostos a aceitar o ruído. © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Publicado por Elsevier Editora Ltda. Este é um artigo Open Access sob uma licença CC BY (http:// creativecommons.org/licenses/by/4.0/). Introduction Hearing aid is one of the common rehabilitative measures for individuals with permanent hearing impairment. In some cases of hearing losses, hearing aids can be used transitory. However, hearing aid users often complain of background noise resulting in rejection of hearing AID.1 Kochkin2 has reported that about 31% of the hearing aid users reject their hearing aid because of background noise. Various outcome measures are available that consider background noise as one of the factors to have an effect on satisfaction with the hearing aid. Unfortunately, these outcome measures are to be administered after a period of experience with hearing aid. Besides measures such as speech in noise test, quick speech in noise test, competing noise test, and hearing in noise test are being used to predict the hearing aid beneﬁt.3 Though these tests are sensitive to measure speech performance in noise and are administered at the time of ﬁtting hearing aid; they fail to predict real-world beneﬁt and/or satisfaction from hearing Aids.4 This issue is addressed partly by acceptable noise level (ANL) measure introduced by Nabelek et al.,5 in which the client rates annoyance due to background noise in the presence of speech. Nabelek et al.6 demonstrated th (...truncated)